Flow Design and Collector Performance of a Natural Circulation Solar Water Heater

Abstract

This paper presents the design and experimental analysis of flow inside the collector of a natural ‎circulation solar water heater. The water heater was constructed and tested at Ado-Ekiti, Nigeria ‎on Latitude 7.5oN. The results show that the system performance depends very much on both the ‎flow rate through the collector and the incident solar radiation. A typical day analysis of the ‎system shows that collector efficiency is high especially around mid-day when the solar collector ‎receives the highest energy. During the test, the results showed that the system exhibited ‎optimum flow rate of 0.1 kg/s.m2 at a maximum collector efficiency of 68.5%. Also, the average ‎daily efficiency of the system was 57.7% and the maximum water temperature obtained was ‎‎83.5oC, while the maximum ambient temperature obtained was 34.5oC‎